KIAWAH ISLAND, S.C. -- Phil Mickelson could have done without the thrills on Saturday in the PGA Championship.
Losing a five-shot lead in a span of five holes on the back nine. One tee shot into the water, another that ended up under a cart tire. It was all part of a wildly entertaining day that ended with Mickelson nearly holing a flop shot that can test the nerves of just about any 50-year-old but him.
That brought Mickelson to the cusp of history not many could have seen coming.
That par save for a 2-under 70 gave him a one-shot lead over Brooks Koepka and left Mickelson 18 holes away from becoming the oldest champion in the 161 years of the majors.
When he curled in the 4-foot putt for par on the 18th hole, Mickelson became the oldest player with a 54-hole lead in a major since 59-year-old Tom Watson at Turnberry in 2009.
That event didn't end well for Watson, who lost the British Open in a playoff to Stewart Cink. For Mickelson, it's an opportunity to become the oldest major champion. Julius Boros was 48 when he won the 1968 PGA Championship.
Asked to describe such an occasion, Mickelson was too busy glancing at his watch. Sunlight was fading, and he wanted to practice. These opportunities don't come along as often as they once did.
"I'm not really dwelling back on what took place today," he said.
Sunday should get his attention, starting with the guy who joins him in the final group. Koepka survived what he called the worst putting of his career. Statistically, he was middle of the pack, but he missed a 6-foot par on the final hole for a 70 that cost him a share of the lead.
No matter. At stake for Koepka is a shot at his third Wanamaker Trophy in four years. No one has won the PGA Championship so often and so quickly since it switched to stroke play in 1958.
"I'm in the final group," Koepka said. "That's what you want."
Mickelson was at 7-under 209. For all his success in the majors -- five victories, runner-up finishes in all four of them -- this is only the third time he has held the 54-hole lead.
Koepka, shaking off effects from ligament surgery on his right knee that has limited him to two tournaments in three months before arriving at Kiawah, wasn't surprised to have another shot at a major. He already has won four of them in the past five years.
"It just feels good, feels normal. It's what you're supposed to do, what you practice for," he said. "I'm right where I want to be, and we'll see how tomorrow goes."
Louis Oosthuizen started the third round tied with Mickelson and had a long, three-putt bogey. The South African never caught up, though he had his chances, until missing a 4-foot birdie putt on the par-5 16th and a 5-foot par putt on the par-3 17th.
He wound up with a 72 and was two shots behind.
"Probably the worst I've played in a while," Oosthuizen said. "I was just sort of fighting to stay in it; and at the end there, started judging the greens wrong, and everything just fell apart. All in all, two behind going into Sunday, I've got to take a lot of positives out of that."
At least they have a chance.
Mickelson broke away quickly with four birdies in seven holes, and he even managed to avoid losing his focus. One distraction came from the fourth fairway, where Mickelson saw a drone in the air left of the green and said to a CBS spotter, "Can you radio to the TV guys to get the drone out of the flight of my shot?" He saved par from a back bunker.
He went out in 32 -- Mickelson played the front nine on Friday in 31 -- and was five shots clear when he walked off the 10th green. Five holes later, the lead was gone.
Mickelson badly missed a 7-foot birdie attempt on No. 11. He pulled his tee shot into a bunker on No. 12 and had to play back to the fairway, leading to his first bogey of the round.
Then he drove into the water on the 13th with his 2-wood, had to hit his third shot from the tee because of where he thought it crossed the hazard line and missed a 12-footer to take double bogey. Ahead of him, Koepka rattled off three birdies.
Mickelson, without so much as a top 20 over the past 10 months, is going after his first major since the 2013 British Open, and the final hour made it clear that this might not be easy.
But it will be loud. The gallery is the largest at a major since the pandemic -- the PGA of America has said there would be 10,000 people, a number that felt far greater -- and Mickelson was the object of raucous shouting.
Kevin Streelman bogeyed the 18th for a 70 and was alone in fourth at 4-under 212, followed by Branden Grace and Christiaan Bezuidenhout of South Africa, each with a 72.
Jordan Spieth matched the low round of the day with a 68, still seven shots behind and most likely too far back to contend with a dozen players ahead of him.
Spieth was headed back to his rental home to flip on the TV, a rarity for him.
But it's Phil. It's theater.
"I don't watch golf, but I promise you I'm going to turn it on to watch him today," Spieth said. "It's pretty incredible. I have no way to relate to it, right? But I also don't think it's necessarily that special, because didn't he win a World Golf Championships in the last couple years?
"The guy's got four good rounds on any golf course in him, and no one would bet against that."
Mickelson has had three good ones at Kiawah Island.
One more for history.